Number of proteins per cell?

I'd like to include some impressive-looking numbers into a in introduction. As usual, the simplest questions are the ones which are hardest to answer:
Does any of you have an idea of how many proteins you have in the average (mammalian) cell? Another way to think about this is to ask which percentage of the genome is actually transcribed in a cell. I can come up with a guess, but with more people guessing it's going to be more accurate